1. Field of the Invention
This invention relates to an improved transfer mechanism in particular, but not exclusively for transferring articles into and out of a confined area such as a vacuum treatment chamber, and to equipment incorporating such mechanisms.
2.Description of the Related Art
Known vacuum chambers might typically employ a rack and pinion type mechanism within the chamber which extends through a port in the chamber and includes a table which can be loaded with work pieces. The table is then retracted using the rack and pinion mechanism into the chamber. The rack and pinion type mechanisms employed in known mechanisms typically achieve a maximum reach out of the chamber of less than 70% of the chamber width or diameter. However it is very desirable to reach further out of the vacuum chamber with a simple transfer mechanism, to improve the layout of the processing area surrounding the chamber. Thus the ratio of the reach of a transfer mechanism compared to the area that it occupies in its closed state is an important benchmark. Where a transfer mechanism is used in a vacuum chamber, for example an ultra high vacuum (UHV) chamber, purely mechanical devices are preferred.
In some instances, it is preferred that a work piece in a confined space such as a vacuum chamber is loaded into the chamber through one port and unloaded through another port. Therefore, it is desirable also that the transfer mechanism employed is rotatable to achieve the different transfer directions.